The present invention relates in general to a stable yet collapsible plant support with removable portable protective cover for use in a private garden or commercial farming operation and in particular to a collapsible A-frame-shaped plant support with a removable protective cover and that is readily installed, stabilized and removed after use for effectively supporting and protecting tomato and other fruit and vegetable plants.
According to Woodstock Wire Works, Inc. of Vernon, Calif., there were, in the late 1990's, more than an estimated 100 million tomato/plant support cages used in approximately 30 million vegetable gardens in the United States. Annually, approximately 40 million more tomato/plant support cages have been fabricated and sold worldwide. The USDA has reported that the U.S. fresh-market field-grown tomato production for 2007 has been over 3.7 billion pounds with a value of greater than $1.27 billion.
There have been a number and variety of plant support structures, including and without limitation round cages, vertical trellises, espaliers, and A-frame supports. These support structures have been used in both home gardens and commercial growing operations to support the sometimes heavy burden of large fruit and vegetables produced on the plants to have been supported by the plant support structure. Where such structures have been made with inferior designs or weak materials, they have buckled under the weight of the fruit, they have been difficult to install, they have broken upon installation and removal, and they have been blown over in windy conditions.
Further, where early planting dates have been critical and inclement weather has been more common, some of these support structures have doubled as support for a portable, removable, cold-frame type greenhouse protective covering as well. Without this protection, crops that have been planted before the last winter freeze has occurred may have been damaged or destroyed by frost damage, which has resulted in damage to the produce and a financial loss to the grower. These cold-frame type greenhouse protective coverings have exacerbated the instability of poorly designed or weak structures, since the protective covering has acted as a wind sail to catch the wind to add increased force to an already over-burdened structure.
U.S. Pat. No. 5,412,905 to Allison, teaches a Tomato Green House plant support structure that has employed an inverted cone shape with cross support members and spike-type legs at the bottom which have been driven into the ground to hold the structure upright. Being an inverted cone shape, increased weight of fruit on the vines running over the ladder-like support bars near the top of the structure, together with wind forces, have caused the structure to be unstable and to topple during adverse conditions. The addition of a protective cold-frame greenhouse type cover to such a structure has added to its instability. A further disadvantage of this type of plant support has been that it has not been collapsible for easy folding and storage.
In practice, such prior art devices, have often been made of small gauge wire and have been constructed with ineffective spot welds. Further, insufficient design consideration has been given to the angle of insertion of the leg extensions of such devices such that undue stress has been placed on the legs as the they have been inserted into the ground. Through repeated use, this stress has caused weakening of the smaller gauge materials comprising the legs of the structure which has led to their premature failure. Owing to the small gauge of the wire construction of such devices, they have been difficult to install and remove, and upon pushing on them to install them, or upon pulling on them to remove them from the ground, they have bent or broken and have at best become useless for further use. Those familiar with gardening can readily attest to the difficulty of removal of lesser quality structures from the ground, there not being sufficient handle to pull on to remove the device, and there not having been provided in the prior art means for facilitating easier removal. This problem has been addressed by the use of smaller gauge wiring which will not have to cut through hardened ground upon removal, but as mentioned previously, this solution has the unfortunate consequence of lesser support for the plant and lesser resistance to bending and breakage of the device upon attempted installation and removal.
Other prior art plant support devices recognizing the virtue of flat storage of a plant support device, for example during winter months, have provided for collapsible or foldable plant support structures. A variety of such devices can be found, such as a Collapsible Plant Support of U.S. Pat. No. 4,019,280 to Summers. The Summers device discloses a generally tri-pod shaped device employing helically-wound wire springs attachable end-to-end to provide a structure for preventing undue spreading of the base of the structure upon installation in the ground. Upon removal of the wire springs, the device collapses for storage. The Summers device provides no gauging means to facilitate easy installation of an A-frame device without over-tensioning the legs of the device. Further, no foot pegs are provided for facilitating the installation of the device in the soil.
A Foldable Plant Support Structure and System of U.S. Pat. No. 6,088,956 to Rocka provides a cylindrical plant support structure that is collapsible to a flat structure for storage. No foot pegs are disclosed for readily installing the device in the ground, and the leg spikes to be driven into the ground are perpendicular to the ground such that no tension is introduced into the frame of the structure upon installation, making it less stable during adverse weather, excess loading or bumping of the device. Further, the Rocka device is subject to instability as uneven loads are added to the device, and this is exacerbated by a lack of static downwardly directed force component on the legs below the surface of the ground for the ground to hold onto the device to counteract such uneven loading. Finally, no gauging system for readily and easily installing the device to the correct depth in the ground is provided.
In U.S. Pat. No. 5,179,799, to Hillestad, a Demountable Tomato Plant Support is disclosed which embodies a plurality of tiers of vertically spaced ring members removably engaging metal rods that are inserted in the ground to stabilize the support. Since the basic shape of the Hillestad device is an inverted cone shape, increased weight of fruit on the vines running over the upper circular ring members near the top of the structure, together with wind forces, have caused the structure to be unstable and to topple during excessive loading and adverse conditions. The addition of a protective cold-frame greenhouse type cover to such a structure has added to its instability for the wind sail effect created as described above.
Other storable plant support devices have been known in the art, including Collapsible Plant Stand of U.S. Pat. No. 7,281,352 to Peck, a Plant Support Constructed for Compact Nesting of U.S. Pat. No. 5,048,231 to Brown, and a Plant Support of U.S. Pat. No. 760,879 to Kunzman. None of these devices has disclosed an enhanced-stability, A-frame structure with means for readily installing to a correct depth and at an optimized tension to maximize stability and appropriate positioning. Accordingly, these devices, in some cases inverted in cone shape, or at best a cylindrical shaped structure with vertically installable legs, have not been designed to provide greater stability as plant loads, adverse weather conditions or other upsetting factors have effected stability.
To the degree the leg extensions of such support structures have been installed perpendicularly to the ground, with the leg extension puncturing the ground without slicing the ground during installation, the legs and depending structures have relied for stability upon the forces of gravity and of friction between the soil, which is variable depending upon the makeup of the soil, and the relatively smooth surface of the leg extensions. This has made the plant support structure vulnerable and subject to lifting out of the ground in the event that an upward force, such as an upward component of a wind force greater than the forces of gravity and friction acting upon the legs of the cold-frame or plant support structure, have been applied. And while increased loads from fruit bearing plants have tended to counteract such upwardly directed vertical force components, it is well-understood that such forces only rarely exist exclusively as vertically upward component forces. Rather, wind forces most often have force components also acting horizontal to the ground, further lending to the inherent instability of devices that extend vertically from supporting legs that are installed into the soil perpendicular to the ground and without sufficient opposing horizontal force components within the structure. This also become a factor for plant stands that do not have a base that is wider than the top of the stand, since such are more vulnerable to wind or bumping forces that would tend to topple the stand.
One prior art plant structure and greenhouse, a Reversible Plant Cage/Greenhouse disclosed in U.S. Pat. No. 5,423,148 to Thornhill, combines a plant cage and a portable greenhouse in a single device. Inverted, the device provides a plant supporting structure, and upright the device provides a greenhouse type structure having spikes that stick into the ground. In the plant supporting configuration of the Thornhill device, the plant support of the device is in the form of an inverted cone and thus is not stabile, similar to the device of Allison described above. Thus, as the weight of fruit, adverse weather conditions and bumping from tools, equipment or persons increases, the design of both Thornhill and Allison have tended to fail to accommodate the forces applied and the devices have toppled. Further, the device of Thornhill is not collapsible to allow for easy storage of the device.
Other prior art plant structures are disclosed that are collapsible and foldable. One of these include the A-frame plant support structure known as Woody's Folding Tomato Cages. These tomato cages are made of rigid wood members, have not been pre-fabricated and have not taught the concept of embedding or otherwise installing the legs of the cage into the soil in such a way as to readily tension semi-rigid and noticeably flexible A-frame members. Further these A-frame plant support structures have not included means for readily installing legs on the device into the soil to enhance stability. As such, the user has simply set these prior art A-frame structures on the surface of the ground creating a less stabile structure in the event of winds, unevenly growing plant loading and/or bumping by other objects.
Rigid A-frame plant support structures would also have had another inherent disadvantage in the angled placement of the legs, in that if it had been attempted to insert the legs into the ground while the legs had been rigidly fixed in relation to each other, as taught in the case Woody's Folding Tomato Cages, the path through which the legs would have traveled into the ground would have remained open, as though having been sliced, and thus the ground would have provided a lesser amount of resistance, relying primarily on friction forces and gravity, to hold the legs of the plant support structure into the ground.
A foot peg, or step, used in conjunction with and to stabilize a plant support has been disclosed in the Plant Stake of U.S. Pat. No. 3,397,485 to Peterson, where a bend in the stake is shown providing a place for a user to step in order to drive the stake into the ground and provide stabilizing forces for the stake while installed. Of course, the Peterson device does not disclose the use of an otherwise stabile structure having a plurality of stabilizing legs and corresponding means for readily installing such plurality of legs into the ground to form a stabilized structure for readily supporting a growing plant.
One prior art cold-frame plant protection device, such as that shown in U.S. Pat. No. 2,014,175 to Hart for a Plant Protector, has employed a portable, cold frame, greenhouse, and has employed leg extensions at the base of the cold frame to serve as pegs or spikes that have been driven into the ground to provide an anchor for the stability of the frame. In this case, the cold-frame type greenhouse has created a wind sail effect that has added to the instability of the frame in moderate to high winds. As a result, the protection device has been pulled out of the ground and blown away, damaging or displacing the supporting cold frame, and this has damaged plants and left them unprotected.
Another example of this type of a cold-frame, greenhouse type device is the Plant Promoting Device of U.S. Pat. No. 2,051,596 to Harbaugh. However, the Harbaugh device has introduced the concept of collapsibility to the structure of the device for flat storage during winter months and also has added s-shaped bends to the spiked legs that have been placed in the soil to allow for the soil to compact around the legs to grip them with downward forces to prevent their untimely lifting out of the ground as with wind forces greater than the forces of gravity and friction acting upon the legs of the cold-frame structure.
Thus, it has been desirable that a sturdy and stability-enhanced plant support structure be devised that is designed to facilitate ease of installation, ease of removal, and provide a standardized structure that easily accommodates a cold-frame type greenhouse protective cover or tent.